Variable displacement pump or motor



Nov. 2, 1937. E. K. BENEDEK I 7 9 VARIABLE DISPLACEMENT PUMP OR MOTOR Filed March 27, 1955 4 Sheets-Sheet 1 ELEKKBENEDEK.

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4 Sheets-Sheet 2 Filed March 27, 1935 Nov. 2, 1937. E. K. BENEDEK 2,097,830

VARIABLE DISPLACEMENT PUMP OR MOTOR Filed March 27, 1935 4 Sheets-Sheet 3 T15- 5- 1 15.412. v ELEK KEJEMEUEK E. K BENEDEK 2,097,830

VARIABLE DISPLACEMENT, PUMP 0R MOTOR Nov. 2, 1937.

4 Sh eets-She'et 4 Filed March 27, 1935' Patented Nov. 2, 1937 UNITED STATES PATENT OFFICE 2,097,830 vsamnm DISIRILACEMENT rum on TOR Elek K. Benedek, Bncyrus, Ohio Application March 27, 1935, Serial No.: 13,294

' 6 Claims. (Cl..103-'--161)- This invention relates to variable delivery ure to maintain proper lubrication of the operating surfaces and also to the manner of transmitting both the torque and the load reactionary thrusts to and from the reactance and the piston heads.

Again, in pumpsor motors of this type con:

I joint problems of assembly and the provision of a light but rigid and stable reactance with a very limited overall radial dimension are presented. The failure to solve these conjoint problems has limited the use and application of this type. of

pumps. r

Some of the limiting factors are that these.

- pumps require a larger radius of rotation to the outermost working. parts with resultant concurrent increases in centrifugal force and peripheral speeds. Again, the mounting of the piston T- heads in the reactance so as to eliminate binding of the heads under hydraulic deflection has not been efiectively solved. Proper cooperation of the piston crossheads and reactance for efllcient torquetransmission has been disregarded enti'rely. The required mass of the rotating parts, especially parts of the reactance means and'the difiiculty of lubricating the working parts efllciently likewise have resulted in decreases in 9f,- ficiency. Again, failure to remove from the parts the heat resulting from fiexure and frictiomhas reduced efliciency.

to provide, in a pump or motor of this character, completely anti-friction torque transmission, as

well as anti-friction load transmission, for driving the reactance rotor.

A correlative object is to effect-this result by maintaining a new cooperative relatinnship be tion of one of the operating levers-for shifting the tween the piston crossheads and-the reactance rotor. 50 Another object of the present invention is to improve the construction of pumps'of this particular type by greatly reducing frictional resistance and heating of the working parts.

Another object is to provide a piston T-head 5 and mounting in which the T-heads are sub- The principal object of the present invention is.

'stantiallyno greater in width transversely of their path of travel than the diameters of the pistons themselves, whereby lateral bending stresses of the heads are substantially eliminated and the overall axial dimension of the pump and reactance assemblage may be reduced'to a mini-' mum.

Other objects are to provide for lightness of the working parts without asacrifice of strength, for reduction of the radius of rotation of the parts and for elimination of localized binding and frictional stresses by more efiectiveIcorrelation of the working parts.

Other important objects are to provide eifective lubrication of all the working parts while the pump is in operation, and to retain lubricant on the parts when the pump is inoperative for long intervals-whereby, .upon 'starting, the parts are fully lubricated.

More specific objects areto provide an improved reactance rotor and housing assembly whereby a more easily assembled, light, smaller diameter, rigid structure may be obtained.

Another specific object is to provide a novel T- head mounting as a, result of which localized binding stresses are substantially eliminated and the radialdimensions of the head itself and of itsjmounting may bereduced,-thus reducing the overall radius of rotation of the pump.

Another specific object is-to provideja self-. aligning control rod or lever for shifting the reactance rotor into different operating -positions whereby assembly is facilitated.

Other objects and advantages will become apparent from the following specification'wherein reference is made to thedrawings in which Fig. 1 is a horizontal sectional view through a pump orv motor structure embodying the principlesof the present invention and is taken on a plane .indicatedby the line l-l in Fig. 2;

Fig, 2 is a verticalcross sectional view of the pump o'rmot'or taken on a plane indicated by the line 22 of Fig. 1, part thereof being shown in elevation and part being taken on the plane indicated by the line la-2a of Fig. 1, for clearness 5 inillustrationi v Fig. 3 is a longitudinal sectional view of a porreactance rotor; p

Fig. 4' is a'longitudinal'sectional view of a subassembly of a slightly,modified reactance rotor and housing;

5 is a view similarto that of Fig. 4, showing another modified form of the reactance rotor'and housing;

Fig. 6 is a fragmentary sectional view of one of the piston heads and cooperating reactance means illustrated in Fig. 2 showing, in exaggerated condition, the relative position of the reactance means and head; and

Figs. '1 to 12, inclusive, are side elevations of a piston of the present structure illustrating, in exaggerated condition, the effects of various working stresses to which the pistons and T- heads are subjected under both load and torque transmission.

Referring to Figs. 1 and 2, the pump or motor comprises a bell shape housing I having a rigid hub 2 at one endand an integral axially extending circumferential wall 3 which forms the main body of the casing. The end of the casing remote from the hub 2 is closed by an end plate 6 through which extends the main impeller shaft 6 of the pump barrel, or delivery shaft in case the apparatus is operated as a motor. Mounted by one end in the hub 2 and extending axially of the casing is a rigid valve pintle 6 which protrudes into the casing and is received in a dead end axial bore of the piston carrying rotoror barrel I. The barrel 1 is rotatably mounted with in the casing and held in accurate coaxial relation to the pintle by suitable sets of anti-friction bearings 8 arranged to withstand both axial and .radial displacement of the barrel. The barrel 1 is providedwith a series of circumferentially spaced radial cylinders 9, each of which is provided with a radial port In communicating with the interior of the barrel bore in position for cooperation with valve ports of the pintle 6.

The pintle is preferably of the hydrostatically balanced type, such as fully disclosed in my copending application Serial No. 754,853, filed November 26, 1934, and is provided with the usual 7 pressure and suction ports II and I2 which successively communicate with the ports III of the barrel. The ports II and I2 communicate respectively with the usual longitudinal ducts l3 and I l respectively, forming the necessary and well known fluid circuit of the pump. Also as more fully set forth, in my above identified copending application, hydrostatic'defiection of the pintle is resisted and proper pintle lubrication is effected by suitable sets of capillary needle roller bearings I51: and l5b, spaced at opposite ends of the valve portion of the pintle, respectively, and engaging bearing surfaces onthe inner wall of the barrel bore. 1 Received in each of the cylinders!) are respective reciprocable pistons l6 each' of which is provided at its outer end with a T-head 20, as will be more fully described hereinafter.

In order to reciprocate the pistons, a reactance rotor is provided. The reactance rotor comprises a pair of rings 25 and 26, the rings being coaxial and of equal diameters and mounted in axially spaced relation.- A reactance housing 21 is provided for rotatably supporting the rings, the housing 21, in turn, having, 'at diametrically opposite portions, external plane bearing surfaces 28 cooperable with corresponding bearing surfaces in the body 3 for supporting the housing with its axis parallel to that of "the barrel, while permitting shifting of the housing'to different positions, either coaxial with the barrel or with its axis eccentric and parallel to thebarrel axis. On outer portions of the housing 21, at 90 to the bearing surfaces 28, are plane parallel stop surfaces 21a which are diametrically opposite withrespect to each other and which cooperate with corresponding plane surfaces 21b on the interior of the body portion 3, for accurately limiting the setting of the housing 21 at maximum eccentricities to either side of the pintle axis. For supporting the rings 25 and 26 within the housing 21, anti-friction bearings 29 are provided. In' the form illustrated in Fig. 1, two

sets of bearings are shown, one set cooperating.

In larger pumps, such as illustrated, especially those in which ball bearings are used, caremust be taken to eliminate heating, noise and wear *of the bearings. Therefore, instead of the usual commercial design, the ball bearings 29 are loosely received between the housing and rings. The balls 29- are insertedby positioning the housing 21 eccentric with respect to the reactance rings 26 and 26 and the required number of balls is placed in the wider space thus afiorded. The rings 25 and 26 are then brought concentric with the housing 21 by shiftingthe balls around the cir- Icumference. The balls are then spaced, evenly by means of retainer rings 30, one ring being provided for each set.- Each ring 30 comprises. a pair of axially separable companion pieces secured together by suitable bolts 90a. The rings are of as little thickness radially as is practicable so asto be accommodated readily betweenthe housing 21 and the reactance rings 25 and 26; The rings 30 are likewise of fibre for reducing the weight. The rings 30 separate the balls from each other, retaining them so that the balls are loosely fitted and may rotate at high speed unimpeded by excessive viscous friction between the balls or friction between the balls and retainer. The elimination of these frictional resistances, which are considerable in tight fitted or present commercial bearings due to displacement of the oil film, is very important. Furthermore, when the balls are thus loosely mounted, it is not necessary that they roll at all times while traveling about the inner race of the housing in an oil film similar to capillary needle bearings until carried to rolling position. Again,

since the fibre rings 30 are light in weight and do not tightly engage the balls, the tangential and radial centrifugal forces imposed on' the balls thereby as they both roll and rotate about the rotary axis are'greatly reduced with a concurrent increase in the efliciency of operation.

For shifting the housing 21, diametrically opposite radial control levers .or rods 9| 'are provided, each of the levers being secured at its inner end to the housing. Suitable bores 3a are provided in the body portion 3, through which .are received rigid tubular-rods-32, the inner ends 32b of which abut the stop faces 21a of the housing 21. The rods 32 are generally coaxial with the rods 3| and surround the latter. Each of the tubular-rods 32 is provided outwardly of the casing with an internal radiaishoulder 32a,

facing toward the outer end of the rod. The rods 3 I- extend outwardly past the shoulders 32001. the respective tubular rods and are provided with a suitable nut 33 having a shoulder overhanging the shoulder 32a. The shoulder 32a and nut-33 cooperate so that upon outward movement of the rods 32, the inner rods 3| will be drawn therewith and upon inward movement of the rods 32,

' they will abut the housing and move it to the required position. The nut 33 is smaller than the inner passage of the tube 32 in which it lies. as also is the rod 3|, so as to permit slight radial shifting and limited self-alignment of the rods 3| and 32. Obviously, as a result of the self-alignment of the/rods 3| and 32 with respect to each other, and the end 321) of the rod 32 withv respect to the housing 21, extreme care which otherwise would be necessary in manu-.

facture and assembly is no longer required. The bores 3a.do not have to be exactlydiametrically opposite and coaxial, as slight misalignment will not causebinding of either the rods'3'l or 32, nor, for the same reason do the threaded bores in the housing 21 in which the ends of the rods 3| are received have to be absolutely accurate in position with respect to each other or to the bores 3a. Again, since the end 32b-of each rod 32 only abuts the housing, and since the rod 3| may shift relative to the rod 32, the housing 21 is not constrained to a fixed-axial position in the body portion 3 thereby but may float a limited amount axially relative thereto. Again, whatever mechanism isrprovided for shifting the reactance rotor housing need not be accurately aligned with the bores 3a, as any slight axial misalignment or tilting will be compensated by shiftingof the rods relative to each other. Likewise, axial compensation can be effected by screwing the nut 33 to desired positions along the rod 3|.

Referring now more specifically to the piston T-heads and the manner in which they are operatively connected tothe reactance rings 25 and 26 for both torque and load transmission; each. of the piston heads 20 protrudes tangentially of its path of rotation both forwardly and .rearwardly from the axis of its associated piston and is elongated in the direction of travel. As set forth in my copending application, Serial No.

138,184,1iled August a, 1934, the T-heads, hereinafter referred to as heads or as. crossheads, are preferably formed integral with the pistons with which associated. The central portions 201:

from torque transmission. The width of the crossheads, that is, the dimension transversely of the path of rotation is the same or very slightly greater than, the diameter of the pistons so that lateral overhang with consequent lateral bending stresses are substantially eliminated and the heads can be subjected only to lateral shear.-

ing stresses-all as will more-fully appear hereinafter in-thediscussion of Figs. -7 to 12 inclusive. The radially outwardly disposed face of each head comprises a, plane tangentially extending bearing surface, normal to the axis of its associated piston.

' [since both rings i and 2e are the same in form and function, merely being placed oppositehr with mpect-to' each other,,and since they cooperate with the piston heads in a correspondthe of the piston with which it is associated when the barrel and ring 26 are set at zero eccentricity. In advance and to the rear of the pin 36, are secondary or torque transmitting rollers 31 and 38 respectively. The radial innermost surfaces of all of these rollers lie substantially in a common plane extending tangentially of the direction of travel. Thus each' group of rollers 36, 31, and define 'a substantially plane bearing surface cojoperable with the outer bearing surface, of a piston head 20. for driving the head on the pressure stroke or,in case of a-motor, for transmitting the. operating pressure stroke to the reactance, and for transmitting torque from thebarrel to the reactance through the medium of the pistons and crossheads As above mentioned, each of the piston heads 20 is provided with a thickened central portion 201:. The end p0rtions,designated'20b, however, are of less thickness so that their inner surfaces are parallel to the outer bearing surface and constitute the inner bearing surfaces of the head. correspondingly, torque rollers 39 and 40 are provided in the ring 26, the rollers 39 and 4|] having their axes parallel to the rollers 31 and 38 and preferably being aligned therewith inplanes therethrough and parallel to the axis of the associated piston. The rollers 39 and 4t engage the inner bearing surfaces of the end portions 201) respectively for moving the pistons on their suction strokes and for cooperating to transmit torque. The inner and outer sets of rollers, therefore, provide, in effect, substantially frictionless guides for transmitting reactions to and from the pistons while permitting the tangential oscillation of the piston heads relative to the reactance rotor for compensating for the tangential components of eccentricity of the barrel and reactance rotor. Since, as will be described more fully hereinafter, each piston crosshead is subject to warping under ing sets of rollers are equidistant from the piston axis. a

Each of the rollers 36 is mounted at its ends in capillary cageless roller needle bearings, as

indicated at 42, so that the rollers are freely rotatable about their respective axes.

For mounting the rollers while permitting ease -=in assembly and disassembly and formaintaining lubricant thereon, the rings 25 and 26 are provided withroller receiving bores 25a and 26a respectively, which bores extend parallel to the axis of the rings and terminate in dead end relation to the more remote ends f the rings. Thesebores open through the inner adjacent faces of the rings and corresponding bores of the respective rings are aligned axially with respect The bores 25a and 26a are proto each other. vided with enlarged coimterbores 25b and 26b, respective y, at their dead ends to allow axial clearance for" the ends of .the rollers 36. Each roller 36 has reduced bearing hubs 36a and 36b whichare. receivedin thebores 25a and 2511 respectively in the capillary needle bearings. The

' torqu'e rollers 31, 38, 39, and 46 are correspondingly mounted in needle hearings in corresponding aligned pairs of dead end bores in the rings 25 and 26 and correspond in shape to the rollers 36, but are less in diameter. The extreme 'ends'of each of the rollers are of slightly greater the hearings in the bores. The rings 25. and 26 are spaced apart so as to receive, with a com- .paratively close but free sliding and capillary fit therebetween, the crossheads (of the pistons. Due to the reduction of radial dimensions at the end portions 20b of the crossheads, the rollers 39 and may readily be accommodated in the rings 25 and 26 more closely to the axis of the piston with which associated without any increase in the radial width of the rings. Consequently, for a ring of given size, more space is available between adjacent ends of adjacent heads for permitting installation of means for fastening rings 25 and 26 together.

Another advantage resides in making the end portions of less thickness, in that the T-head is more nearly a constant strength beam and can flex more efllciently to permit substantially a complete transfer of all pressure reactance forces by and to the roller 36 and cooperate with the torque rollers for transmitting torque to the re actanc'e rotor. The advantages of full strength at the piston are also retained. As better illustrated in Fig. 2, between adjacent piston heads, there are provided in the rings 25 and 26, aligned bores extending parallel to the axis of the rings, .through which bores are received bolts for fastening the rings 25'and 26 together. Each bolt 45 is in screw threaded engagement with the ring 26 and is provided with a head 44 which is snugly accommodated in a counterbore in the ring 25 and engages a shoulder formed at the juncture of the bore and counterbore fordrawing the rings relatively together. The counterbore is of'sufi'icient depth so that no part of the bolt head 44 protrudes beyond the end of the ring 25. As heretofore explained, it is necessary for efiicient operation, that the working parts be effectively lubricated. Necessarily, during operation of the pistons, a certain amount of fluid slip therepast occurs, this fluid traveling to the outer end of the pistons and their heads. In order' to retain the proper spacing between adjacent faces of the rings 25 and 26 when assembled and to retain lubricant on the working parts, an annular circumferentially closed spacing ring 46 is provided, the ring 46 being slightly oyersize axially relative t0.t he width of thepiston crossheads so that the rings 25'and 26 may be drawn against the ends of the ring in firm sealingengagement while permitting only capillary clearances for the crossheads. When so fastened with the bolts 45, a deepcircumferentially closed annular trough opening radially inwardly is provided in which the slip fiuid is constrained against discharge by centrifugal force for main taining sufficient lubricant on the heads and rollers. The dead end bores in which the hubs of the rollers are received communicate with this trough for receiving lubricant therefrom.

Referring more specifically to the necessity for.

and manner of accomplishment of proper lubrication, as mentioned above, the rollers for the crossheads are mounted in anti-friction capillary needle bearings. While the pump is operating, the slip from the pistons is thrown outwardly by centrifugal forces and by the ring 46 is maintained in. position for lubricating the working However,

parts of the pumping assemblages. when the pump is temporarily shut down, this oil tends to drain by gravity to the bottom of the lil pump body. -If, after a considerable period, the a pump were again started, the working parts would normally have no lubricant and, under the severe starting stresses, would be required to operate with substantially no lubrication for an interval. The needle bearings, however, retain lubrication when the pump is shut down by the formation of capillary films so that upon starting and through the accumulated oil drained therein.

Consequently, they are relubricated almost imme-' diately.

The failure to provide for this lubrication or maintenance of lubricant during the period in which the pump is shut down completely is one of the primarycauses for rapid wear and failure. Necessarily, when the pump first begins operation, the power requirement for a given output, due to inertia and frictional losses, is very high and when these must be withstood by substantially unlubricated piston heads, reactances, and moving parts, extreme wear and stresses, often accompanied by immediate freezing of the working parts as well as excessive heating result. Evenafter the pump is in operation and lubricant is provided, the heating of the working parts continues. As is well known, air spaces and the like constitute an effective insulating medium against heat transfer.- With the annular trough and communicating bores for the rollers filled with fluid, this heat may readily be transmitted to the fiuid figom all the working parts and by it carried or retransmitted to parts from which the heat can be more readily dissipated into the air or into the fluid passing through the pump.

Referring next to Figs. 4 and 5, modified forms of reactance units for meeting special needs are illustrated, the parts therein corresponding to the same parts in Fig. 1, being numbered with. corresponding primed and double primed numerals respectively.

Fig. 4. illustrates a reactance unitfor use in connection with the pump described having certain advantages over that shown in Fig. 1. This unit comprises companion reactance rings 25' and 26' mounted in a housing 21', these parts corresponding tothe rings and housing in Fig. 1, and designated therein by corresponding unprimed numerals. The rings 25'and 26 are provided .with sets'of axially aligned bores 25a and 26a extending parallel to the axes of their rings." At

the dead ends of the bores 25a. and 26a the same are counterbored, as indicated at 25b and 26b to. slightly greater diameter and provide axial'clearance between the end walls of the bores and the" ends of the'crosshead rollers to be received there-' in. On their radially outward surfaces, the rings engagement with the ring 46' a series of circum of the ring 46'.

26' may be drawn firmly together against the accuses are provided with radially extending annular shoulders 50 and 52 respectively, the shoulders being positioned near the outer margins of the rings, respectively. Circumferential bearing surfaces extend from the shoulders entirely to the inner ends of the rings for receiving and mounting internal races 49 and 53 respectively of the ball bearings 29'. T hese internal races. snugly embrace the circumferential surfaces of the rings and terminate at their inner ends flush with the inner ends of the rings on which they are carried. At their outer ends, the races firmly engage the shoulders 50 .and 52 respectively.. Disposed intermediate the rings is'anannular circumferentially closed spacer ring 46' correraces 49 and 53, the ring 46" being slightlyigreater than the width of the piston heads so that the heads may be snuglyreceived between the rings and maintain the capillary clearancetherewith.

For drawingthe rings flrmly together and into ferentiaily spaced bolts 45', each having a head 44' are provided, the ring 26' having a number of threaded bores to receive the threaded ends of the bolts 45' andthe other ring having corresponding bores for receiving the bolts. The bores in the ring 25' are counterbored to accommodate completely the heads 44' of the bolts. The housing '21 terminates at its ends in the planes of the outer ends of the rings 25 and 26' and is provided with internal circumferential axially extending surfaces which accommodate the outer races 48 and 5! of the bearings 29'. Intermediate the surfaces engaging the races 48 and ii, the housing 21 is provided with a radially inwardly extending circumferential boss 54 having, at each end, radial shoulders engageable with the inner ends of theraces 48 and 5| respec-' tively for limiting axial shifting of the races. The length of the boss 54 is slightly less than that Consequently, the rings 25' and spacer without danger of pinching the bearings 29 by axial oifset of the inner races relative to the corresponding outer races, the outer races necessarily accommodating themselves in alignment with the inner races. The outer races, therefore, are, in effect, free floating within certain limits. If these provisions are not made, there is danger that the bearing will be gripped too tightly'in the races and consequently will be destroyed almost immediately upon operation of the pump. 1.

It should be noted ,that the bearings 29' are positioned directly over the bores 25a and 26a respectively so that the thrusts therefrom are transmitted directly to the crosshead rollers and bending moments are eliminated,

In some instances it is desirable to reduce the radial overall dimension of the unit, in which instance the unit illustrated in Fig. 5 is highly desirabie. This unit is substantially the same in every way as the unit in Fig. 4 except that capillary needle bearings 29" are utilized instead of the bearings 29f and greater relative axial movement between the housing and reactance rotor is aiforded: In using the capillary needle bearings, no supplemental races are necessary; Instead, shallow circumferential troughs are provided on the exterior of the rings 25" and 2B" in which the respective sets of needle bearings are disposed. The housing 1:1, in turn, is provided .rods 3|" and 32" thereto.

with internal circumferential bearing surfaces having no intervening boss corresponding'to the boss 54 in Fig. 4. Thus the bearings 29" with the rings 25" and 26" may shift axially relative to the housing 21". Five distinct advantages are provided by this arrangement, namely; the rotary reactance formed by the rings 25" and 25" may shift axially with the primary rotor or barrel; I the load transmitted through the bearings '29" is transmitted over a distance axially of the rings substantially corresponding to the full length of the hearings in which the crosshead rollers are mounted in the bores 25a" and 26a" instead of being concentrated within rela tively narrow limits; in addition to reducing the overall radial dimension, the bearings 29" retain a capillary film-while the pump is inoperative so that when it is again started, lubrication is present; the floating of the rings 25" and 26" relative to the housing 21" permits the housing to shift to accommodate itself to the rings as the barrel is adjusted in operating position, and due to the relative self-alignment of the control rods 3!" and '32", eflicient control may be provided therefor in the shifted condition. Lastly,

in assembling the pump, it is only necessary to place the pistons in the barrel cylinders, drop the torque and load rollers in their bores respectively in one of the reactance rings, position the piston heads between their rollers, place the spacer 46" in place, and clamp the other reactance ring firmly against the spacer 46", and then, after placing the needle bearings 29" in position, slide the housing 21" therearound. The assemblage of the reactance unit.and pump barrel may then be slid into place in the body of the pump and the barrel flxed in proper position, the reactance rings necessarily-adjusting themselves in proper axial position relative to the barrel. The housing .21" may then be shifted axially to the extent necessary for connecting the contro Referring nextto the piston crossheads and their cooperation with the load and torque rollers, these actions are fully illustrated in Figs. 7 to 12 inclusive. In Fig. 10, is illustrated a normal piston and integral crosshead substantially full size, in unloaded condition, both so far as concerns hydrostatic load and torque transmission. The median line of the crosshead is designated :c-lll and the center line of the piston designated y-IB. It is pointed out that both lines :c-'-l 0 and yi0 are straight lines lying 90 to each other.

In Fig. 7, the condition of the piston under maximum hydraulic load and without any effects of driving torque, is illustrated, the force to forces R. The centerline y|' of the piston re-' mains undisturbed and straight;

Referring next to Fig. 8, the piston'is shown under the influence of driving torque only, this torque, designated -M1, is being imposed on the piston through the cylinder bore wall by the forces QQ-. This couple or moment must be resisted and is, in fact, resisted by the reactionary forces T, one of which forces is transmitted to the crosshead by one of the outer rollers 31 or 38 and the other is transmitted by one of the inner rollers39 or 40 at the opposite side of the piston axis from the active one of the rollers 31 and 38.v

- curve of the third order, that is, defined by an transmission, is eflected.

equation having one of its unknowns raised to the third power. The efiects illustrated in Fig. 8 are due to torque transmission alone and not to load transmission. This condition may occur, for example, at full stroke operation when thetransmitting power and torque are, great enough to stress the piston and crosshead. It may also occur without the application of maximum pressure as in those cases in which the pintle becomes too tight in the barrel or some pair of barrel bearings become too tight.

In Fig. 9, the combined effects illustrated in Figs. 7 and 8 are shown, this combined effect being produced when the piston is at maximum pressureand maximum torque, as when the pump is operating under full stroke and full pressure to provide maximum power. The piston centerline y-9 is the graphic addition of the lines y'| and y 8; and the median line a:-9 of the cross-, head is a graphic additionof lines :r'| and a:-8

of Figs. '7 and 8. It is apparent that these two separatg and distinct forces, namely: load and torque ransmission, result in not only warping the crosshead itself but in twisting it backward relative to the normal axis of the piston. It is also flexed outwardly intermediate its ends by the hydrostatic load at the same .time the piston is deformed by the couple Ml, which is the driving couple. It should be noted that since the forces and power developed by each piston are very great and the piston dimensions relatively small, the lever arms through which the couples M1 and M2 are developed are relatively small. As a result the forcesproducing the couples necessarily are correspondingly large and, in fact, are

of considerable magnitude. For a piston such as illustrated in the figures, the force P is about 3000 pounds, or one and'one half tons, the reaction forces RR being correspondingly great. The driving forces are about one tenth as great,

the piston crossheads and the torque rollers is illustrated more specifically, this again being the cooperation only insofar as torque transm ssion is concerned. From --Fig. 11 it is apparent that by cooperation of the rollers 31 and l0 with the corresponding opposite ends of the crosshead,

torque may be transmitted positively and by direct thrust even while maintaining anti-friction rolling connection-between the respective rollers and the crosshead. Thus, for the first time, so far as the present inventor is aware, anti-friction torque transmission, as distinguished from load In Fig. 12, there is shown the cooperation of the piston head withrollers 31 and 33 under the action of the force P only, an effect explained inconnection with Fig. 7. As stated, any possibility that the deflected ends 20b would be pinched by the rollers is eliminated by provision of the slight clearance designated II, which is provided by spacing the corresponding end rollers 31, 39 and 38, 40 a slightly greater distance apart than the thickness of the corresponding portions of the crosshead.

Thus the crossheads are always in engagement with the load roller 38, and also concurrently with one outer torque roller and one inner torque roller positioned at the opposite side of the piston axis from the then active outer torque roller. 0n the suction stroke, the torque rollers are immediately effective, and no play-or, slack with its known effects is present.

It is apparent that a straight tangential guide I would not provide the result desired but instead the piston crosshead would be warped and twisted therein so that it could nottravel therealong to compensate for the tangential components of eccentricity of the rotors. Instead the ends of the crosshead would tend to dig in the guide.

Since free tangential travel, positive and emcient suction without slack in the crosshead engagement, heavy hydrostatic load, and driving torque must be provided simultaneously for, efficient and satisfactory operation, it will be seen that the torque rollers in combination with the roller 36 will meet all of these conditions.

While, during the pressure period, the greatest were relied upon for reactance delivery. In the present structure, howeverpthe overhang is so hydrostatic load is on the roller 33, the torque slight, as well illustrated in Fig. 1, that the bending forces are not effective and the head need be made to withstand shearing forces only at opposite sides of the path of travel.

Thus a heavy portion is provided in the middle of the crosshead for the direct load transmission and the outer extremities of the head in the path of travel may flex and accommodate themselves to the torque rollers so as to maintain an antifriction torque transmitting relation therewith at all times without danger of breaking off of the heads..

A positive driving connection between the pistons and the secondary rotor is accordingly provided as distinguished from frictional driving connection, or driving connection through the bolts and the rotors. The bolts 45 are solely for the purpose of drawing the reactance members in place against the spacer ring and have nothing to do with torque or load transmission.

From the foregoing it is apparent that com- 'plete anti-friction torque transmission is provided, centrifugal, forces are reduced, both by a reduction inthe radius of rotation of the parts and in the mass of the parts; peripheral speeds are likewise reduced, excessive heating is eliminated and lubrication is maintained during both inoperative and operating periods. Furthermore. the entire structure may be readily assembled and disassembled for repairs,: service and replacement, and, when assembled, is extremely compact and durable.

. Having thus described my invention, I claim:

1. In a rotary radial piston pump or motor of the character described, including a barrel, 'circumferentially spaced pistons carried thereby, a

reactance rotor eccentric to the barrel for reciprocating the pistons consequent upon concurrent rotation of the barrel and rotor, heads respective to the pistons, each head protruding tangentially of its path of travel in both directions from the piston with which it is associated and having tangential outer bearing surfaces and inner bearing surfaces at the end portions, said surfaces being parallel with respect to each other, load rollers carried by the rotor, each roller being in rolling engagement with the outer face of the piston. head with which associated normally at the axis of the particular-piston for moving the piston on the pressure stroke while permitting tangential oscillation of the head with respect to the reactance rotor, torque transmitting rollers carried bythe rotor and engaging the inner bearing surfaces of the heads respectively for moving the piston on the suction stroke, each head being concurrentlyvin rolling engagement with both the outer and inner rollers associated therewith, additional torque rollers carried by the rotor and engaging the outer surfaceof the heads respectively adjacent the zone of the said innerrollers, said additional rollers being spaced from the inner rollers a distance slightly greater than the radial thickness of the portion of the head received therebetween for permitting free deflection of portions of the head and for guiding the head while in the deflected condition.

2. In a rotary radial piston pump or motor of the character described, including a barrel, circumferentially spaced pistons carried thereby, a reactance rotor eccentric to the barrel for recip rocating the pistons consequent upon concurrent rotation of the barrel and rotor, heads respective to the pistons, each head protruding tangentially of its path of travel in both directions from its associated piston and having a tangential outer bearing surface and tangential spaced inner bearing surfaces parallel to said outer surface, said inner bearing surfaces being at opposite sides of the piston axis, outer central and end rollers carried by the reactance rotor and spaced longitudinally of the head and engaging the outer surface-of theheadboth at'its central portion and end portions, and additional inner rollers carried by the rotor and engaging the inner bearing surfaces of the head, said outer end rollers and inner rollers being spaced apart a distance slightly greater thanthe radial dimension of the end portions of the head for permitting inward flexure of the head by the outer central roller, un-' constrained by theouter end rollers.

3. In a pump .or motor of the character described, including a barrel and radial piston assemblages carried thereby, and a reactance rotor eccentric to the barrel and cooperable withthe piston assemblages for' reciprocating the same consequent upon concurrent rotation of the barrel and rotor, said rotor comprising coaxial axially spaced matched rings, a circumferentially closed annular spacer received therebetween and coaxial therewith, the ends of the spacer engaging said rings outwardly from their radial inward margins in fluid sealing engagement therewith, whereby a circumferentially closed trough is formed, companion dead end bores in said rings parallel to the common axis thereof, said coaxial bores being in pairs, each opening toward the other and through the adjacent spaced face of the other ring with which associated, piston-actuating rollers having their ends received in said bores, one roller to each pair of bores, each roller having a central roller portion and end portions protruding therefrom, means for securing the rings in fixed coaxial position in sealed relation with the spacer with said pin end portions of the rollers in said dead end bores, said dead end bores being of greater diameter than the said ends of the rollers for receiving cageless' rollers for rotatably supporting the piston actuating rollers, the roller portions of the piston actuating rollers being larger in diameter than the portions which engage the cageless rollers and being coextensive axially with the space between the rings, whereby, when the rings. are secured together, the piston actuating rollers are mounted therein and the cagelessrollers are retained in operating condition by the rollers.

4. In a pump or motor of the character described having a piston carrying barreL-a reactance rotor, and a reactance rotor housing and means mounting and guiding the housing for movement to different positions while retaining the housing with its axis parallel to the axis of the barrel, a control rod for moving the housing, said controlrod comprising a rigid tubular rod abutting, at itsinner end, the said housing and extending radially outwardly therefrom, and parallel to the guide means, means mounting the tubular rod for axial movement parallel to the guide means, a rigid rod loosely received within the tubular rod and fixedly connected at its inner end to the housing, said tubular rod having an internal radially extending shoulder facing away from the housing, said rigid rod protruding away from the housing beyond said shoulder, and means on the protruding portion of the rigid rod having a shoulder overlying the said radial shoulder and securing said rods for outward movement together, and said means being less in size than the portion of the tubular rod in which it is located, whereby the rods may shift relatively radially and compensate for slight axial misalignment of the rods.

5.In a rotary-radial piston pump or motor of the character described, including a barrel, circumferentially spaced pistons carried thereby, a reactance rotor eccentric to the barrel for reciprocating the pistons consequent upon concur-4 ment with the load bearing surface, and torque transmitting means spaced longitudinally of the head and engaging the outer torque surfaces of the head, and additional inner torque transmitting means carried by the rotor and engaging the inner torque surfaces of the head, the associated outer and inner torque transmitting means being spaced apart parallel to the piston axis a distance slightly greater than the spacing of the load transmitting means and the inner torque transmitting means.

6. In a pump or motor of the character described having a barrel, an adjustable reactance,

piston and cylinder assemblies and means niount- 7| 8 aoo'nsso ing and guiding the adjustable reactance for movement to different adjusted positions whilev commgidating said tubular rod, a second rod connected to the reactance and lying within the first tubular rod with clearance radially of the rods,

and means connecting the rods for axial move- .ment together and limited radial movement concurrently, whereby the rods may shift relatively radially of each other and compensate for axial misalignment.

' ELEK K. BENEDEK. 

